Read/write Color Space in Nuke Dpx for Resolve

As a Resolve colorist and Flame/Fusion VFX artist, I've done my fair share of VFX compositing, rotoscoping, keying, object removal, tracking, and basically any other VFX process you can recollect of. I've also managed shots that had to be sent out to vendors all over the earth, and wrangled pipelines of major commercials and features.

In all that time, I've learned firsthand the ins and outs of different types of VFX workflows, and truly appreciate how difficult information technology is to build i from the basis up.

But I've also come to realize that VFX pipelines aren't something to be scared of. Once we empathize the fundamental components and how they fit together, it's fairly easy to build new workflows that fit our detail creative needs and technical resource.

In today's article, I'll lay out several best practices for VFX workflows. Nosotros'll cover the basics of building your own VFX workflow from acme to lesser, and assist answer questions on everything from hardware and software choices, to setting upward proper colour direction, binder structures, and file naming conventions for your projection.

Many of these recommendations are tailored to smaller teams handling 2D compositing-type effects, just most of the principles will apply to large 3D/CG every bit well. So there'south something here for everyone interested in VFX workflows.

Allow'south dive in.

A piddling background

In the onetime days (pre-digital conquering), film negatives had to exist scanned before any sort of VFX could exist added to a scene.

This conversion process from an analog, physical, chemically-processed medium to a digital video/prototype file requires circuitous processes to ensure all the captured dynamic range, color, and detail of a shot remains intact for VFX teams.

The scanning procedure was (and nonetheless is for film-based workflows) a key factor in preserving the highest visual quality from the camera negative.

Lots of really smart people poured buckets of money and time into developing and optimizing the best methods for scanning picture show. The better the scan, the ameliorate the canvas for VFX teams to work their magic.

Thankfully, we now bask the benefit of inexpensive, ultra-high-quality digital cameras. The files that come up off digital cameras unremarkably have everything we need to work on proper VFX.

That said, even though we don't "have" to browse film anymore (although many high-stop productions still elect to shoot on movie), the analog to digital process is still a major consideration for VFX workflows. Except at present instead of it happening in a lab somewhere, information technology happens right behind the lens.

Analog scenes, digital files

Like flick scanners, digital camera sensors capture analog information (the low-cal data entering the lens) and catechumen and encode it into digital files. Though, sometimes the camera merely stores the raw calorie-free data (that'due south what a raw file is).

Let's imagine you're planning a shoot for a VFX-heavy scene. What is the optimal capture format? Well, information technology depends, but let's showtime with the basic question—should you capture raw or RGB?

While information technology'due south truthful that raw formats preserve unrivaled levels of paradigm detail, they tin can be problematic for VFX. That's considering many raw formats capture videos into multiple files (1 file per frame for some formats), rather than a single convenient file that wraps all the frames together.

Obviously, this can cause bug for VFX teams who take to pass files between multiple users/machines/departments/facilities. Adding hundreds or thousands of individual files per shot to the process can be disruptive, non to mention time consuming, since raw files are quite large.

On top of that, the nature of raw footage would require every user to re-encode and debayer the raw files in order to work with them. That only slows downwardly the procedure farther and increases the run a risk for errors.

So, while capturing in a raw format is more often than not a good idea and will deliver the highest-quality prototype for your projection, you'll probably want to catechumen the footage to another working format before information technology reaches your VFX workflow.

But let's say you desire to keep things simple, and you lot don't desire to bother with re-encoding the raw files. To salve time, yous choose to shoot your scene in a log format. They're pretty skilful at capturing dynamic range, and with a 10-scrap encode they leave lots of room for image manipulation during mail-production.

Log files are a lot easier to piece of work with in your postal service pipeline because you won't accept to exercise whatever of the crazy raw workflow gymnastics just to pass the files effectually. But they can make some VFX processes more difficult, like certain types of keying or compositing.

If raw and log are both problematic, what capture formats and types of files make the near sense for VFX work? How do you effectively preserve the highest-quality image from a photographic camera sensor all the way through post, while also choosing a format that won't slow you downward or make your piece of work difficult?

There are many potential answers to these questions. Ultimately, the right respond for you depends on the project and the blazon of VFX you need and the resources available.

And since most of the time your resources will be tied to the sort of work you're doing, let's take a wait at the about mutual types of VFX.

Types of VFX work

When almost people think of VFX compositing, they think of explosive superheroes, fantastical CGI worlds, or epic action sequences. Piece of work like that is unremarkably only possible with huge teams responsible for private sequences.

The workflows for these shots are planned far in accelerate by VFX supervisors and team leads. They decide the file types, working color spaces, folder structures, and naming conventions during pre-product.

While this blazon of VFX work for major blockbusters is what almost people recall of when they hear VFX, it's just one facet of the larger world of VFX work.

In commercial work, for case, VFX tin be much more subtle, like removing a reflection from a car, painting out a blemish on skin, or shrinking someone'due south waistline. Here, the thought is to keep the effects mostly invisible.

Small teams are quite capable of this type of VFX, just their workflow will look much unlike than that of a larger project. For commercial work, a team might be working on 4 entirely different jobs that use completely different cameras, all at the same time.

That ways the VFX workflow will have to be flexible enough to handle many different capture formats, and may not do good from the same degree of pre-planning that the large workflows have.

Needless to say, this necessary flexibility can make project arrangement and shot management less predictable than on characteristic work. And many small teams won't have a dedicated postal service supervisor or engineer backside them to go along the projection rolling when technical problems popular upward. In some cases, individual artists might exist in charge of edifice and maintaining their ain workflow.

Without that kind of back up, VFX work can get really complicated really chop-chop. Balancing the technical demands of the workflow with the creative tasks of the project tin can go challenging.

Information technology tin be hard to make these types of workflow decisions if you're building a new VFX pipeline, since at that place are so many factors to consider. So permit'southward accept a pace back and demystify the overarching process and considerations. That way we'll get the most out of our tools and have a better understanding of their capabilities.

Considerations for VFX Workflows

In that location are a few major things to consider when deciding on an appropriate workflow for a project. And these considerations are all interdependent on each other. That means that if you have to change one, yous'll likely have to adapt the residual of the process.

For example, your colour pipeline could be dependent on which piece of software you lot employ. And the slice of software you need will influence the hardware yous choose. That hardware might impact which file types/formats you can use efficiently. So on.

It'due south important to expect at each of these workflow categories with the large picture in mind.

Here are the major considerations you need to consider when building a VFX workflow:

• Color management
• File format
• Resolution and bit-depth
• Software
• Hardware
• Naming conventions and binder structure
• Budget and time

While not required in every instance, I find it helpful to think about these decisions in this order. Information technology makes it easy to see what choices are dependent upon the other.

Colour Management

Earlier deciding on any workflow, color management of the project is probably the most important factor. Why? Considering making sure the image data is displayed, transformed, and stored correctly will make or break the VFX.

There are two major approaches to colour management for VFX: scene-referred and brandish-referred. There's a lot to unpack with these workflows, merely I'll quickly review the nuts here.

Scene-referred information reflects the low-cal values of the real-world scene as it was captured, instead of a conforming that data to particular color space.

Brandish-referred data, on the other manus, encodes the sensor information to a target color infinite, and applies a gamma curve to the image file.

Scene-referred

If y'all've ever shot raw footage, y'all've dabbled in a scene-referred format. With this type of workflow, you have to catechumen the linear light values into a displayable format every fourth dimension you lot want to work with them.

A lot of major feature films or high-end projects use linear light workflows, so every bit you can imagine in that location are a lot of moving pieces.

For example, if you were compositing a shot in a linear light workflow, y'all'd take to convert the shot for viewing with a brandish lut or output transform to do any work. So, in one case you finished compositing the VFX, you'd have to render the files back into linear light (remove the display transform) in order to preserve the linear light values.

This arroyo makes many aspects of compositing improve, like blending, considering the math running backside the scenes is much more than precise.

Linear workflows also brand delivering to multiple formats easier. Since no gamma curve or color space is automatically assigned to the prototype data, you tin render to whatsoever commitment color space you desire (or just continue them in a linear light format for archival purposes).

Every bit newer, better display formats are adult, you lot could have these same renders and convert them into those newer brandish formats to take advantage of wider colour spaces and increased dynamic range for HDR standards.

But these benefits come up at a cost. Transforming between colour spaces, keeping files organized, and making certain all the metadata survives as files are passed down the pipeline can experience like a full-fourth dimension job (and in many workflows, it literally is). That'due south why with a smaller squad or project, a scene-referred workflow might exist overkill.

Display-referred

For less complicated workflows, like commercial, corporate, and even tv workflows, display-referred workflows are often the common selection.

If a testify or commercial is simply going to exist broadcast, or exist streamed online, and then you simply need to cater to ane delivery format. That means you can save a lot of time by working in that delivery color space.

With brandish-referred workflows, files aren't converted when they're imported. The project'southward color space volition probably simply exist the color space the photographic camera encoded the files to, and VFX are made to match this brandish output. You only need to render scenes to this associated color infinite.

But of course this simplicity sacrifices flexibility. One time you decide on a mastering format, that'south it. All your files will be bound to that color space. This may not be an issue if you don't need to deliver multiple color spaces or delivery destinations, so the weight of this determination will depend on the demands and expectations of the project.

File Formats

In one case you have your color management figured out, choosing a file format is a relatively like shooting fish in a barrel determination, but it'southward still important.

It's disquisitional to understand the limitations and strengths for any potential file formats before yous beginning using them in your workflow. I of the most important factors when choosing a file format is how the data is stored within that particular format.

There are ii main methods for storing digital information: integer and floating point. These may sound complicated, but stick with me.

Integer data means that data similar RGB values won't contain decimals. They are represented by whole values (no decimal places) within a predetermined range.

Floating betoken data, in dissimilarity, stores decimal places and can encode values across the set range.

What are the benefits of each approach?

In general, floating point values yield improve results for VFX. Since there are more than numbers bachelor to calculate, the conversion betwixt various color spaces and compositing operations is more accurate. This makes floating point files more than desirable in a scene-referred type workflow.

Integer files, by dissimilarity, aren't as accurate when going back and forth to linear from log or other transforms, considering rounding errors stack upwards. Since numbers tin only be integers, estimations are made in each conversion, which leads to inconsistency and artefacts. That said, single conversions to a brandish colour infinite are common with integer formats, and so they work fine within a display-referred workflow.

To compare the two more directly, floating point type files are great for compositing work. Just for color grading, integer files tend to work ameliorate, since most grading applications yet run best with log encoded integer data.

That's why if your projection has a lot of CG integration work, OpenEXR files may be the best file format to use. Since OpenEXRs can store scene linear data, you'll maintain all the benefits of that workflow, as we discussed earlier.

But if the VFX needs for a project are more invisible, like scene cleanup and objects removal for broadcast work, an integer-based format like log DPX or ProRes444 will work just fine. Log-based or display-referred workflows simplify the process considerably, since those color transforms are well divers and less complicated than scene-linear transforms.

Resolution, Scrap-Depth, and Compression

The next important consideration for your workflow is the resolution and fleck-depth of your shots.

In nigh workflows, at that place is a compromise between source resolution and deliverable resolution. Some modern movie theatre cameras can shoot upwards to 8K resolution, so your plates can theoretically be that large, but 8K VFX plates would deadening down VFX work to a crawl.

However, if editorial is going to use a lot of push-ins, or your deliverable format is 4K, then 1080P will be way likewise small-scale.

Bit-depth is also an important consideration. If you're heavily manipulating color, you'll need access to a big range of digital values. For integer work, ten-scrap is the standard, but for floating betoken, 16-bit float is usually the best choice.

Finally, compression as well plays a major role for VFX pipelines.

When making VFX plates and renders, for example, the pinch method used will dictate what blends together or stands in the scene. If the compression used on the plate doesn't friction match what was used on the composited elements, the visual continuity of the shot volition likely be cleaved.

For my recommendations higher up, OpenEXR files offering flexible compression options to match betwixt elements, and can be optimized to save bulldoze space and hardware load. But ProRes444 is much more compressed than DPX files, which volition speed things up at the cost of lossless quality. QuickTimes are not usually used in college end VFX workflows for several reasons, but if drive infinite and hardware are a business, they can work.

For projects with quicker turnarounds or lower budgets, keeping file sizes smaller and scrap-depths depression (10-bits minimum) will speed up workflow. The most suitable choices will depend on your projection.

Of course, you'll demand to know how your files will be used upstream to decide on resolution, bit-depth, and pinch. Picking a happy medium between the lossless quality and usability/speed is generally the best choice, but finding that sweet spot will be dependent on your hardware and software capabilities.

Software

There are more options than e'er for VFX work these days, simply I'm going to focus on the iii most common applications for compositing work:

• Nuke
• Flame
• After Effects

Nuke works in scene-referred infinite by default. If Nuke is the software of pick for your teams, then OpenEXR files will exist the best option. In fact, we can all thank Nuke for scene linear workflows, OpenEXR files, and floating bespeak formats. These technologies were less popular prior to the advent of Nuke.

If Flame is your preferred workbench, note that it too can use scene-referred data. That said, Flame is traditionally more commonly used in broadcast situations, which are obviously display-referred. Using a scene-referred workflow with Flame is a bit more complicated than with Nuke, as DPX files are the common choice in Flame workflows.

When it comes to Subsequently Effects, things tin can go catchy. Color direction in After Furnishings is more difficult to line up, especially since Afterward Effects is layered-based (rather than node-based). Piping input transforms and output transforms for scene-referred workflows is difficult.

That'southward why, typically, Afterwards Effects work isn't scene linear, and the virtually common file formats are QuickTimes and paradigm sequences similar .tiff, targas, or .pngs (usually in integer flavors, though floating betoken is an option).

Because larger budget projects usually call for the highest quality (i.e. scene-referred) workflow, Nuke is the kickoff choice for most large productions. Just medium and modest projects can leverage the power and speed of Flame and Later on Effects for incredible VFX, especially if all they need is display-referred outputs.

Hardware

Hardware is the next consideration when building a VFX workflow.

High quality files generally take up more space, and require more than processing power. Many of you will be intimately familiar with hardware bottlenecks, and sadly there really isn't a manner to get around them other than upgrading to a more powerful system.

In particular for VFX pipelines, the image files we use most often, like OpenEXR sequences, are taxing and have up tons of storage.

That said, if your work doesn't crave the highest terminate workstations, then you tin build a very efficient pipeline without breaking the bank. In fact, spending extra coin for hardware (similar more storage than you demand or processing power that goes unutilized) will practise you more than harm than adept.

Thankfully, systems keep getting faster and cheaper, and it'due south easier than ever to scale your compute and storage resource as your business grows.

Naming Conventions and Binder Construction

Naming conventions and folder structure are an integral office of any VFX workflow. Every unmarried asset in your pipeline will need a carefully thought out proper noun and place to live, from plates to renders and everything in between. If y'all skip this step, you're setting yourself up for a earth of hurting and suffering.

File Names

Information technology can be difficult to decide what information to include in a file name, what type of metadata to embed, and where to put the files. In my experience, the almost important information to include in a VFX shot is the shot number, unique shot proper noun, version number, and embedded timecode.

I also call up shot numbers are a must for VFX shots, as they can be tracked in a workflow tracker or database. This makes it easy to bank check their condition, and go along upwardly with vendors.

Whatever you choose, organization and consistency are cardinal, peculiarly with larger teams. If even just a few assets are mislabeled or put out of place, your workflow can come to a screeching halt.

Folder Structure

VFX work involves a lot of moving files around. Plates are rendered out from OCNs, they're imported into a scene, and so composited scenes are rendered out. Information technology's important to determine upfront where source plates and rendered composites (and the many other types of avails VFX generates) will live.

Again, shot numbers are a necessity. Shot numbers go on plates, graphics, and all associated elements of a VFX shot together and organized.

In my experience, dated folders (like you lot might have for OCNs) are disruptive for VFX shots, especially with complicated projects. Shot numbered folders, on the other mitt, make a lot more sense, peculiarly if version numbers are added to further eliminate the need for dates.

Project Needs

You'll need to appraise the needs for your particular project when deciding on folder construction and naming convention. It's important to residuum how much information should be included in the file name with how easy these file names are to read/use.

If you're using shared storage/servers, shared media, and multiple artists, it's absolutely critical that everyone has buy-in on the naming convention, and maintains consistency for the duration of the project (and every project). This tin can be a claiming during the rush to stop, only it'southward the merely way to keep your workflow from falling apart.

In some cases, different departments might have their own servers and file naming conventions, and they may pass off finished composites/elements to the adjacent squad section who might also have their own storage and file naming practices. Simply for environments with any sort of centralized asset management, establishing protocols that stretch beyond your entire organization (and that are followed past vendors) is paramount.

Upkeep and Time

The single biggest consideration you need to brand when building your VFX workflow is the available budget and fourth dimension.

As a VFX artist, 1 of the most important skills you tin can learn is predicting how much time something will take. Each of the considerations we've already discussed volition determine how much time information technology volition have to finish a VFX shot, and y'all need to make sure that the process you build aligns with the allotted resources.

A good style to make sure you'll stop on time and on budget is by testing your workflow before beginning a projection. As yous exam, and gain experience with your pipeline, yous'll get a much better thought of how long certain processes take, which makes calculating fourth dimension savings or increased burden from pipeline changes easier.

If more than complicated projects crave scene-linear work, your tests volition give you a baseline to calculate the extra piece of work from and figure out how many actress artists and time are required to get it done. Or if a production only needs display-referred renders, and you lot're used to scene-referred piece of work, y'all'll have an thought of how much faster you can end the project.

It's as well important to assess the skills of your team. If a job will stretch existing skill sets, you should add more time into the schedule. But if a projection has an astonishing team atomic number 82, it might have that person half the time to do something it would take a inferior artist to practice.

Speed vs. Quality

Another matter to consider is speed vs. quality. If speed is more important than quality, lower resolutions and pinch volition save fourth dimension and no one volition observe. Some customer budgets don't ever allow for the highest quality workflows, and that'southward ok.

Only if quality is the most important gene, and customer budgets are high (not a common scenario, merely we can dream), and so information technology's fourth dimension to invest in the personnel and machines to make information technology happen.

In the real globe, compromise between quality and speed is necessary, even at the upper-end of the market. More and more, leaner VFX teams accept made inroads to top tier clients, peculiarly equally off the shelf software and hardware take become more attainable.

Perhaps counterintuitively, surviving in the market is difficult for larger, more capable teams, because customer demands are always evolving, while the prices you lot can accuse clients keep falling. Big workflows require large investments in pipeline, software, and hardware, along with the engineers and personnel to back up that investment, only that investment quickly becomes obsolete whether or not it has paid for itself.

Ultimately the most important consideration is whether or not your workflow volition help yous attain the goals of a specific project. The more you programme ahead, the more than successful and productive your VFX workflow will exist.

Boundaries and flexibility

With that in mind, there's a specter that volition likely hover over your VFX pipeline which y'all'll have to face eventually: client boundaries.

As Hollywood has shown us time and again, major VFX projects can produce incredible artistic achievements, but lead to the ruin of the squad who created it all.

Information technology is absolutely crucial to fix expectations and boundaries with clients early on, based on the allotted budget and time frame. If changes are requested during the projection, the actress costs incurred must exist communicated to the project. Of course, artists and producers should be flexible to make sure the client'south needs are met, but not at the expense of the team's mental, physical, or financial prosperity.

Likewise much flexibility and capitulation to client demands can lead to artist burnout and the demise of your concern. If it tin happen to Oscar-winning teams, information technology tin can happen to you.

If customer requests start to pile upwardly, information technology'south crucial to prepare better boundaries based on the budget. This is why it's important to have time at the start to accurately appraise and factor in time for changes or unforeseen hurdles.

Producers and Client Relationships

Client relationships are a huge part of the planning procedure, likewise.

If your client expects you lot to requite them a apartment bid, and there isn't a clear understanding near revisions or additions, you're setting yourself up for disaster. Establishing common respect betwixt the client and your team is essential, and building boundaries will help ensure that respect is maintained.

This is why talented mail-production producers or supervisors are so valuable. They can manage clients, track costs, communicate changes to artists or hurdles to clients, and more often than not keep the projects on task and on upkeep. Having 1 of the artists human action as a producer tin can make things difficult, so, if possible, upkeep money for a producer/project managing director into your workflow.

After many years in this business, I know how difficult it is to prepare these boundaries. Getting a shot or a scene just right may take extra hours or days or weeks. Just with the right support, healthy lines of communication, and a sharp producer watching your back, VFX piece of work doesn't need to be painful. It is possible to deliver loftier quality work in a reasonable time frame within upkeep. But it takes practise and experience.

Decision

VFX workflows are complicated. At that place are so many factors to consider, and it takes years of experience to accurately estimate time and to piece of work with clients effectively. On pinnacle of that, the technical skills of this industry keep evolving at a breakneck pace. But if you call up about the steps nosotros just covered, you'll be well on your way to building a successful VFX team and pipeline.

As you continue to examination your workflow and to learn past completing projects, y'all'll meliorate understand how to plan and budget, and learn the circuitous dance of client interaction.

Successful VFX teams need to communicate, encourage ane another, and all push in the aforementioned management to move a project over the line. I hope you lot found this overview useful and wish you the very best of luck on your journey into the world of VFX!

nunezbetion.blogspot.com

Source: https://blog.frame.io/2020/02/17/vfx-workflow-best-practices/

Share this post